Chemical Composition of Volatile Oils from Leaves and Flowers of Sideritis congesta Using Direct Thermal Desorption - Two - Dimensional Gas Chromatography - Time - of - Flight Mass Spectrometry

Abstract

Volatile oils from the leaves and flowers of Sideritis congesta, a plant endemic to Southern Anatolia, Turkey, were liberated using direct thermal desorption (DTD) and then analysed using comprehensive gas chromatography (GC × GC) coupled with time-of-flight mass spectrometry (TOF-MS). Two methods of thermal desorption are compared here; i) a manual direct cryo cooled on-column collection and focusing, and ii) a fully automated two stage carbon adsorbent thermal desorption system. 41 different volatile components were identified associated with plant leaves and 54 components for the flowers. A comparison of the flower volatiles resolved using the different thermal desorption methods indicated 43 common components, but with the cryo-cooled on-column method giving a slightly better determination. Major organic constituents observed from this species were Opinene (12.53–14.55 %), ß-pinene (17.15–25.34 %) and ô-cadinene (10.97–14.52 %). Results for manual and automated DTD methods are similar: both of them allow a fast plant volatile analysis without the costly and time consuming step of extraction or distillation. © 2008 Taylor & Francis Group, LLC.